Overexpression of ATG8 in Arabidopsis Stimulates Autophagic Activity and Increases Nitrogen Remobilization Efficiency and Grain Filling. (8th November 2018)

• Record Type: Journal Article
• Authors: Chen, Qinwu; Soulay, Fabienne; Saudemont, Baptiste; Elmayan, Taline; Marmagne, Anne; Masclaux-Daubresse, C�line
• Is Part Of: Plant & cell physiology. Volume 60:Number 2(2019)
• Page Start: 343
• Page End: 352
• Publication Date: 2018-11-08
• Subjects: 15N labeling -- Nitrogen use efficiency -- Nutrient recycling -- Resource allocation -- Sink–source -- Yield; Plant physiology -- Periodicals; Microbiology -- Periodicals; Cytology -- Periodicals; Cell Physiology -- Periodicals; Plant Physiological Phenomena -- Periodicals; Cytology; Microbiology; Plant physiology; Periodicals; 571.205
• DOI: 10.1093/pcp/pcy214
• Languages: English
• ISSNs: 0032-0781

Abstract

Abstract: Autophagy knock-out mutants in maize and in Arabidopsis are impaired in nitrogen (N) recycling and exhibit reduced levels of N remobilization to their seeds. It is thus impoortant to determine whether higher autophagy activity could, conversely, improve N remobilization efficiency and seed protein content, and under what circumstances. As the autophagy machinery involves many genes amongst which 18 are important for the core machinery, the choice of which AUTOPHAGY ( ATG ) gene to manipulate to increase autophagy was examined. We choose ATG8 overexpression since it has been shown that this gene could increase autophagosome size and autophagic activity in yeast. The results we report here are original as they show for the first time that increasing ATG8 gene expression in plants increases autophagosome number and promotes autophagy activity. More importantly, our data demonstrate that, when cultivated under full nitrate conditions, known to repress N remobilization due to sufficient N uptake from the soil, N remobilization efficiency can nevertheless be sharply and significantly increased by overexpressing ATG8 genomic sequences under the control of the ubiquitin promoter. We show that overexpressors have improved seed N% and at the same time reduced N waste in their dry remains. In addition, we show that overexpressing ATG8 does not modify vegetative biomass or harvest index, and thus does not affect plant development.